In order to obtain the whole lens’ surface information, measurement of larger diameter optical plane was implemented by using smaller caliber interferometer. The problem of precise location was solved by the plane Givens transform of markers’ position. Each sub-aperture’s tilt and piston were removed by Zernike polynomial fitting. Global optimization stitching model was established. Nine sub-apertures stitching computer simulation was accomplished by using the model. The relative error values of PV and RMS are both about 10-6. A lens of 150 mm in diameter was used in nine sub-apertures stitching experiment. Compared with full caliber interference measurement results, the relative error value of PV is 0.36% and the relative error value of RMS is 2.27%. Simulation and experimental results indicate that the algorithm reduces the requirements of high precision rail in traditional sub-aperture stitching interference measurement.